The present invention relates to the field of photographic image projection and, more specifically, to a video signal output slide projector for converting an optical image recorded on a 35 mm slide transparency into video image signal form.
In industrial audio/visual systems and consumer-oriented "electronic home entertainment centers", the standard color television broadcast receiver or a color video monitor is fast becoming the preferred medium for displaying all types of text and pictorial information. In addition to displaying regular TV programs, TV sets are used to portray video information provided from cable TV systems, video tape recorders, video disc players, low-cost home TV cameras, home video games, and personal or small business computers.
In the photographic field, there have been some indications over the past few years that consumers, as well as audio/visual professionals, are turning away from slide transparencies in favor of reflection prints or some other formats, e.g. video tape, to present photographically recorded images. Some of the reasons proposed to explain this trend suggest that it is too bothersome to set up a projection screen and projector for slides, and the requirement for the room to be almost completely dark for good slide viewing inhibits ancillary tasks such as note taking at business conferences or other meetings.
Because the 35 mm slide does provide a very convenient and relatively low-cost way to record high-quality photographic images, it is highly desirable to integrate this medium into video display systems.
One type of device known in the prior art for facilitating the conversion of optical images on slides to video image signal form is a film/video multiplexer unit which serves as an optical coupling interface between the projection lens of a conventional slide projector and the objective lens of a video camera. Such multiplexer units tend to be awkward to use and rather larger because major portions of their structures are dedicated to supporting the projector and video camera in precise alignment with the multiplexer optics.
Also known in the prior art are professional film/video converters that combine a slide projector and video camera in an integrated package. These devices are generally used at TV stations or at audio/visual service companies that specialize in recording slides, photographic prints, movies, and graphic art on a video tape. However, these converters tend to be quite large and expensive because they must be constructed in a rugged fashion to withstand the rigors of almost constant use.
None of the film/video multiplexers or converters on the market today serve the needs of the small audio/visual department or readily fit into the "electronic home entertainment center" concept because they are excessively expensive and/or large, and in some instances so complex to use as to require a technically trained operator.
Therefore, it an object of the present invention to provide a compact, low-cost and easy-to-use video slide projector.
It is also another object to provide such a video slide projector which utilizes major portions of conventional, off-the-shelf, slide projector and a home video camera, and combines them in a unique packaging scheme to provide a very compact configuration.
Yet another object of the invention is to provide such a video slide projector with a simple mechanism for moving the camera relative to a slide holder for focusing purposes.
Other objects of the invention will, in part, be obvious and will, in part, appear hereinafter.